Bellows forming method and apparatus



April 1, 1969 A. M. MlNNlS BELLOWS FORMING METHOD AND APPARATUS Filed July 14. 1966 Sheet of3 MNNR April 1, 1969 A. M. M INNIS BELLOWS FORMING METHOD AND APPARATUS Sheet 3 drs Filed July 14, 1966 2 m N. E O a m, WM m N T IM F 2. Na Q 1 M M \m. M

April 1, 1969 A, mmcmms 3,435,651.

' BELLOWS FORMING METHOD AND APPARATUS Filed July 14. 1966 Sheet 3 of 3' firraeusws.

United States Patent 3,435,651 BELLOWS FORMING METHOD AND APPARATUS Andrew M. McInnis, Covina, Califi, assignor to Associated Piping & Engineering Co., Compton, Calif., a corporation of Texas Filed July 14, 1966, Ser. No. 565,236 Int. Cl. B21d 15/06, 51/12 US. Cl. 72-105 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates generally to the formation of bellows corrugations in the wall of metallic tubing. More specifically, the invention concerns novel apparatus and method for forming such bellows corrugations in such unusually advantageous manner as to overcome a number of problems arising in connection with the operation of prior bellows forming equipment.

Bellows forming apparatus in the past has suffered from certain disadvantages, including the tendency to undesirably thin the wall of the tubing subjected to roll forming. This result at least in part arose due to need for preliminary forming of a large number of corrugations or convolutions, for proper axial positioning of the roll elements. While such wall thinning might be relatively minor and be acceptable for thin wall tubing, attempts to simultaneously roll a large number of corrugations or convolutions in thicker walled tubing would subject the latter to significant and unacceptable wall thinning. Also, prior equipment lacked many of the unusually advantageous features and results characterizing the present apparatus and its mode of operation. These include the capability to form bellows rapidly on both thick and thin walled tubing, without undesirable section thinning or stress riser formation.

Basically, the method of the present invention for imparting bellows configuration to the wall of metallic tubing involves the use of first, second and third roll flanges, and includes the following steps:

(a) locating the first roll flange to rotate in peripheral engagement with one side of said wall,

(b) locating the second and third roll flanges to rotate in peripheral engagement with the opposite side of said wall while initially maintaining said second and third roll flanges spaced apart,

(c) transmitting rotary drive to effect rotation of the tubing and roll flanges, and

(d) relatively bodily displacing the roll flanges for causing the first roll flange to progressively bulge the tubing wall into the space between the second and third roll flanges and for effecting a reduction of said spacing as the tubing rotates, while maintaining the tubing substantially free of axial constraints imposed thereon other than through the rolls.

Typically, the above steps are carried out to form one annular corrugation in the tubing wall, the tubing is thereafter shifted bodily axially relative to the roll flanges, and the steps are repeated to form a second annular corrugation in the tubing wall, s-uch shifting and forming being repeated to accomplish forming of all the desired corrugations.

In its apparatus aspects the invention contemplates the provision of a first forming roll flange located to rotate in peripheral engagement with one side of the tubing wall; second and third forming roll flanges located to rotate in peripheral engagement with the opposite side of that wall, those flanges being peripherally spaced apart; means to transmit rotary drive for eflecting rotation of the tubing; and other means for relatively bodily displacing the roll flanges for causing the first roll flange to progressively bulge the tubing wall into the space between the second and third roll flanges as the tubing rotates and for controlling the spacing between the second and third roll flanges, the roll flanges imposing substantially the only axial constraint on the tubing. Typically, the first roll is located internally of the tubing and the second and third rolls are located externally thereof; the mentioned other means includes actuator structure operable 1 to reduce the spacing between the second and third rolls and also to reduce the spacing between the axis of the first roll and the common axes of the second and third rolls, all of which axes are substantially parallel; an additional flange is provided to cooperate with one of the second and third flanges to receive and retain therebetween 'a previously formed bulge in the tubing wall for shifting the tubing axially during reduction of axial spacing between the second and third roll flanges, and the means to transmit rotary drive includes drive rolls in peripheral rotating and guiding engagement with the second and third rolls, the drive rolls supported on a carriage which is subject to bodily displacement by an actuator relatively toward and away from the tubing.

These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following detailed description of the drawings, in which:

FIG. 1 is a side elevation showing a preferred embodirnent of the overall apparatus;

FIG. 2 is a section taken on line 2-2 of FIG. 1;

FIG. 3 is a section taken on line 33 of FIG. 1;

FIG. 4 is a section taken on line 44 of FIG. 1;

FIG. 5 is a fragmentary showing of the forming roll flanges during the forming operation;

FIG. 6 is an enlarged vertical section taken through one of the external rolls and its support;

FIG. 7 is an exploded perspective showing of a set of idle rolls; and

FIG. 8 is a vie-w like FIG. 5 but showing another stage in the forming operation.

Referring first to FIGS. 1 and 5, the invention contemplates a first forming roll flange such as is seen at 10 located to rotate in peripheral engagement at 11 with one side of the wall 12 of metallic tubing 13, the first forming roll flange being typically rotated interiorly of the tubing and having an axis 14. Second and third forming roll flanges, as for example those designated at 15 and 16 are located to rotate in peripheral engagement at 17 and 18 with the opposite side of the tubing wall 12, the roll flanges 15 and 16 being peripherally spaced apart. As will be described, rotary drive is transmitted to effect rotation of the tubing and the roll flanges. For this purpose, the roll flanges 10, 15 and 16 may be positively driven in rotation while in engagement with the tubing wall 12 for rotating the tubing about its axis 19 during the forming operation. In addition, the roll flanges are subjected to relative bodily displacement, as for example in the manner to be described, causing the first roll flange 10 to progressively bulge the tubing wall at 11 into the space 20 between the second and third roll flanges 15 and 16, bodily displacement of the latter in addition effecting a reduction of the spacing 20- as the tubing rotates, and to an extent as is depicted in FIG. 8 wherein the opposite sides 21 and 21a 3 of the bulge are collapsed into adjacency to the opposite sides of the roll flange 10.

In this regard, the tubing during such forming remains substantially free of axial constraint imposed thereon other than through the rolls, whereby the tub-ing is free to shift axially as required during sequential forming of the bulges, thereby obviating thinning of the metal Wall sul jected to bulging. It should be noted however that means may typically be provided at one of the rolls, as for example roll 15a associated with flange 15, to shift the tubing axially during reduction of the spacing 20. For example, such means is shown in FIG. 5 in the form of an additional flange 22 on the roll a and cooperating with flange 15 to receive and retain therebetween a previously formed bulge 23 in the wall 11, that bulge extending annularly about the tubing. As will appear, the roll 15a may be relatively shifted toward the roll 16a associated with flange 16 in order to reduce the width of the space 20 during roll forming, such axial shifting of the roll 15a serving to axially displace portions of the tubing 13.

Coming now to an overall description of the apparatus, it will be seen from FIG. 1 that rotary drive is transmitted to the internal roll flange 10 from a hydraulic motor 24 to the horizontal arbor 25 to which the roll flange 10 is removably attached at 26. The latter facilitates attachment of different size roll flanges 10 to the arbor. From the motor 24 the drive is transmitted through suitable reduction gearing 27 through a stub shaft 28 carrying a sprocket 29, shaft 28- being supported at bearings 30 and 31 within the framework 32. The sprocket 29 drives the chain 33 and a larger diameter sprocket 34 attached to the arbor 25, thereby achieving further speed reduction. The heavy or large size arbor 25 is journaled in suitable heavy duty bearings 35 and 36, the construction being such as to practically eliminate bending deflection of the heavy duty arbor at the location of the roll flange 10' under operating conditions.

Rotary drive is transmitted to the external roll flanges 15 and 16 from a hydraulic motor indicated at 37 as supported on the carriage 3 8. That motor transmits drive via the speed reducing gear box 39 to a shaft 40 and additional gearing at at the opposite side of the carriage. From gearing 41 drive is transmitted at reduced speed to drive rolls 42, 43- and 44 as via the gear train generally indicated at 45 in FIG. 3. Train 45 includes a spur gear 46 drive by gear 41 and keyed to a gear 47. The latter drives gears 48 and 49 which in turn drive gears 42a, 43a and 44a associated with the rolls 42-44. The latter drive rolls cradle and frictionally peripherally drive the idle rollers 50 and 51 in such manner that the idle rolls are capable of relative axial movement as between the position seen in FIG. 5 and FIG. 8. In this regard, the latter two figures show the idle rolls 51a and 5112, the former having fixed mounting on stub shaft 52, and the latter being slidable along that shaft, as is clear from the exploded view showing of FIG. 7.

The idle rolls of each set 50 and 51 have peripheral grooving as seen at 53 and 54 in FIG. 5 for receiving the roll flanges 15 and 16 in peripheral driving engagement whereby rotation of the idle rolls transmits rotation to the roll flanges during the various positions of the latter, as is clear from FIGS. 5 and 8. Further, the idle rolls support the roll flanges to resist deflection thereof which would tend to tilt the common axis 55 from horizontal, during the forming operation. The construction produces a forced balancing etfect since the idle rolls engage the roll flanges at points which are opposite from the points of roll flange engagement with the tubing, with respect to the axis 25.

Comparison of FIGS. 5 and 8 will show that the spacing between the axes 14 and 55 is reduced during the forming operation, i.e., during bulging of the tubing wall into the space 20 between the second and third roll flanges 15 and 16. The means for effecting such bodily displacement of the roll flanges to reduce the spacing between the axes 14 and 55 may typically include actuator structure generally indicated at '60 in FIG. 5, as well as the carriage 38, a cross member of which appears at 38a. The actuator may take the form of a fluid pressure cylinder '61 seen in FIG. 1 and a piston rod 62 having attachment to member 38a at 63. The carriage is guided at 64 by the frame 32 for vertical movement. The latter carries the rotary drive elements described above for the roll flanges 15 and 16.

Finally, the means to control or reduce the spacing 20 between the roll flanges 15 and 16 may typicall include other actuators 65 and 66 on the carriage and operable to etfect controlled relative bodily displacement of the roll flanges 15 and 16 along the axis 55. For this purpose the actuators may have connection to the roll flanges as by the link 67 seen in FIG. 6, support 68 pivotally connected at 69 to the link to hinge up and down, a bearing housing 170 carried by the support 68, bearing assembly 171 and the roll supporting the roll flange, as for example the roll 16a seen in FIG. 6. The same construction is usable for the roll 15a and roll flange 15 as well as flange 22 on roll 15a. Accordingly, as the roll flanges are rotated they are subjected to vertical bodily displacement and relative horizontal displacement. Pins 94 may be pulled to facilitate substitution of rolls 15a and 16a of different flange sizes, after dropping of the carriage 38.

A control is shown at 70 in FIG. 1 as having hydraulic control connections at 71, 72, 73, 74 and 75 respectively to the hydraulic motor 24, the actuators 65 and 66, the hydraulic motor 37 for speed and torque control of lower rolls 15 and 16, and the elevator 61. Corresponding manual controls for adjusting the operation of the actuators, motors and elevator are indicated at 71a75a. The latter are adjustable by the equipment operator to achieve control of the forming operation for producing bellows convolutions or corrugations without thinning of the tubing wall, for a wide range of tubing sizes and wall thicknesses.

Finally, the tubing ma be supported as upon the adjustable arms at points 81 and 82, those arms being attached to the carriage 38, thereby to allow axial shifting of the tubing during the forming operation as described above. Prior to bellows formation, the tubing may be formed from a flat sheet of metal which is subjected to circular bending and welding of sheet edges brought into adjacent relation. The weld is cold worked by the bellows forming process of the invention, for strengthening.

I claim.

1. In apparatus to impart bellows configuration to the wall of metallic tubing:

(a) a first forming roll flange located to rotate in peripheral engagement with one side of said Wall,

(b) second and third forming roll flanges located to rotate in peripheral engagement with the opposite side of said wall, said second and third roll flanges being peripherally spaced apart,

(0) means to transmit rotary drive for effecting rotation of the tubing,

(d) and other means for relatively bodily displacing the roll flanges for causing the first roll flange to progressively bulge the tubing wall into the space between the second and third roll flanges as the tubing rotates and for controlling the spacing between the second and third roll flanges, the rolls imposing substantially the only axial constraint on the tubing.

2. Apparatus as defined in claim 1 in which the roll flanges have generally parallel axes, the second and third roll flanges being coaxial, and said other means is operable to reduce the spacing between the first roll flange axis and the common axis of the second and third roll flanges.

3. Apparatus as defined in claim 2 in which the first roll is located internally of the tubing and the second and third rolls are located externally of the tubing.

4. Apparatus as defined in claim 2 in which said other;

means includes actuator structure operable to reduce the axial spacing between the second and third rolls during said reduction of spacing between the first roll axis and the axes of the second and third rolls.

5. Apparatus as defined in claim 4 including means to shift the tubing axially during said reduction of axial spacing between the second and third roll flanges.

6. Apparatus as defined in claim 5 in which said last named means includes an additional flange cooperating with one of the second and third flanges to receive and retain therebetween a previously formed bulge in said wall.

7. Apparatus as defined in claim 2 in which said means to transmit rotary drive includes drive rolls in peripheral rotating and guiding engagement with the second and third roll flanges and said other means includes a carriage for said drive rolls and actuator structure to bodily displace the carriage toward and away from the tubing.

8. Apparatus as defined in claim 7 in which said other means includes other actuators on the carriage operable to effect controlled relative bodily displacement of the second and third roll flanges thereby to control said spacing between the second and third roll flanges.

9. Apparatus as defined in claim 7 in which said means to transmit rotary drive includes an arbor mounting the first roll flange and receivable endwise into the tubing interior, and a rotary drive for rotating the arbor.

References Cited UNITED STATES PATENTS 971,838 10/1910 Fulton 29454 1,597,206 8/1926 Mallory 72105 1,648,046 11/1927 Fulton 29454 1,844,469 2/ 1932 Grisler et al 72105 2,781,075 2/1957 Russel 72105 3,143,794 8/ 1964 Martin-Hurst 29454 CHARLES W. LANHAM, Primary Examiner.

A. RUDERMAN, Assistant Examiner.

US. Cl. X.R. 113116; 29454 

